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哪位朋友能提供一下原文:http://www.pnas.org/content/early/2011/04/14/1102454108.abstract: D6 I w- U5 T8 t2 W
" @* a2 O, L3 ?- CNormal and neoplastic nonstem cells can spontaneously convert to a stem-like state
6 m" U8 [. U f# D9 W9 I( uChristine L. Chaffera,b, Ines Brueckmanna, Christina Scheela,b, Alicia J. Kaestlia, Paul A. Wigginsa, Leonardo O. Rodriguesa,b, Mary Brooksa,b, Ferenc Reinhardta,b, Ying Suc, Kornelia Polyakc, Lisa M. Arendtd,e, Charlotte Kuperwasserd,e, Brian Bieriea,b, and Robert A. Weinberga,b,f,1
8 A! |! i. I9 f! m+ Author Affiliations; ]6 K/ g8 _4 o4 {3 C: W4 E
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aWhitehead Institute for Biomedical Research, Cambridge, MA 02142; . J! n" }" |; X. y N2 J
bLudwig MIT Center for Molecular Oncology, Cambridge, MA 02139; % L& a9 F- m5 O* ^. c
cDepartment of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115;
% ~8 e# q+ k9 ]; i; ~dDepartment of Anatomy and Cellular Biology, Sackler School, Tufts University School of Medicine, Boston, MA 02111; # U ?9 U4 o8 B' k. M5 D6 B
eMolecular Oncology Research Institute, Tufts Medical Center, Boston, MA 02111; and 4 g1 H9 b( W1 W: h# n3 D
fDepartment of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
7 w! C9 k( ?3 s! O& Z2 bContributed by Robert A. Weinberg, March 2, 2011 (sent for review December 8, 2010)
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•The authors declare no conflict of interest.4 I6 [4 }% z) T4 ?( u# M; c" U/ Q3 F
4 d7 |: R. |+ l2 z; Z* M- f6 YAbstract
; V2 y/ z Z/ p( \0 M) b/ @( o- r2 g" YCurrent models of stem cell biology assume that normal and neoplastic stem cells reside at the apices of hierarchies and differentiate into nonstem progeny in a unidirectional manner. Here we identify a subpopulation of basal-like human mammary epithelial cells that departs from that assumption, spontaneously dedifferentiating into stem-like cells. Moreover, oncogenic transformation enhances the spontaneous conversion, so that nonstem cancer cells give rise to cancer stem cell (CSC)-like cells in vitro and in vivo. We further show that the differentiation state of normal cells-of-origin is a strong determinant of posttransformation behavior. These findings demonstrate that normal and CSC-like cells can arise de novo from more differentiated cell types and that hierarchical models of mammary stem cell biology should encompass bidirectional interconversions between stem and nonstem compartments. The observed plasticity may allow derivation of patient-specific adult stem cells without genetic manipulation and holds important implications for therapeutic strategies to eradicate cancer. $ f3 y! l" z0 N' |3 G1 D0 V
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(简译)8 h! s% x5 q+ Y8 S8 G* V- d/ V8 i( }
流行的干细胞生物学理论认为,正常干细胞以及肿瘤干细胞位于细胞层阶的最顶端,单向分化为非干细胞的子代细胞。与这个假说相反,我们在乳腺上皮细胞中找到一种基底样细胞亚群,他们可以自发地去分化而成为类干细胞。我们并且发现,组织癌变可以增强这种细胞自发转化,即非干肿瘤细胞可以在体内及体外产生类肿瘤干细胞。我们进一步揭示出,正常来源细胞所处的分化状态在很大程度上决定了转化后细胞的行为方式。这些发现表明,正常干细胞以及肿瘤干细胞可以反过来由高度分化的细胞所产生,因此现有的乳腺干细胞生物学层阶模式需要修订,以整合这种干细胞与非干细胞之间双向转化现象。所观察到的这些细胞可塑性可能有助于不用基因改造而获得患者特异性成体干细胞,而且对彻底清除癌细胞具有重要的意义。
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5 h& \4 k' V2 E8 W3 C(如果这个现象在其它肿瘤中,在其它病理状态和组织中,甚至在非病理状态中得到验证,将对体内直接转分化研究甚至细胞的生物可塑性有很大推动。不过,很多干细胞现象的一个普遍问题是“幅度”(scale),即这些现象是否具有足够大的“规模”,可以产生明显的生理和病理效应。iPSC甚至胚胎干的体外效率仍旧很低,成体干的很多现象也大多处在“概念证明”阶段。退一步说,即使体内没有足够大的自然过程,如果能够方便地在体外人为“放大”这个过程,达到实用的地步,也可以反过来证明可塑性的存在,尽管是“虚拟”的存在。这大概是最难的。另一个相关的理论和实践问题是这些体内体外的“可塑性”的本质是什么,残留?病态?拟或是人们希望的正常生理状态。) |
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